Cream the butter until fluffy (use an electric mixer set at medium speed).
Add the egg yolk, confectioners' sugar, and whiskey.
Continue beating for 5 minutes.
Sprinkle the orange rind over the batter.
Gradually add the flour, stirring with a wooden spoon until smooth.
Drop from a teaspoon onto an ungreased cookie sheet.
Drop a tiny bit of marmalade onto the top of each cookie.
Bake in a 350° oven for 10 to 15 minutes, or until delicately browned.
Transfer to a tray and let stand until cool.
Dust the tops with confectioners' sugar (put through a sieve).